Development and Evaluation of Grape Preservative Tablets with Precise Sulfur Dioxide Release

In order to solve the problem of food safety, environmental pollution and poor preservation effect caused by high residual and release instability of grape preservative tablets, a new grape preservative tablet with precise release performance was developed. Based on the direct compression method, the preparation technology of precise release grape preservative tablets was optimized by combining single factor and response surface experiments. Compared with commercial grape preservative tablets, the application effect of the preservation tablets on Muscat Hamburg, Red Globe, and Crimson Seedless grape storage were also investigated under simulated commercial storage conditions. The results showed that the best formula for precise release of grape preservative tablets was as follows: The dosage of sodium metabisulfite, microcrystalline cellulose, maleic anhydride, sodium carboxymethyl starch, superfine silica powder andmagnesium stearate were 73.25%, 19%, 5%, 1%, 1%, and 0.75%, respectively. Its SO₂ residue ratio in tablets after four months' use was only 6.42%, while the qualified fruits ratio of Muscat Hamburg grape could reach 95.07%. Moreover, the novel grape preservative tablets had better antiseptic and preservation effect on grapes. The average ratio of qualified fruits and SO₂ residue in flesh of the three grape varieties were 91.89% and 5.12 mg/kg, which were much better than the control group's 86.13% and 17.23 mg/kg(P<0.05). The novel grape preservative tablets had stable SO₂ release, low residue in grape flesh, excellent preservation effect. It also provided good disintegrability, which would be helpful for releasing completely after storage and working in a green and safe way.